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FM sound designer

Original four-operator patches. Start from a recipe, hold C4 or Space, and edit. Begin with low device volume. Host gain defaults to 0.15, capped at 0.3. No listening endorsement or physical-device certification.

Recipe

Patch name Algorithm (0–7) Feedback (operator 1) Modulation index Quality MIDI note Velocity Host gain 0.15

No audio created. Click Start.

Signal graph

Arrows point from phase modulator to recipient; carrier arrows reach output. Feedback is the two-sample averaged operator-1 loop. Topology, selective targets, level, detune, waveform and modulation-index changes retrigger a held gate; ratio, feedback, ADSR and LFO depth/rate use native live controls.

LFO

Rate Hz AM depth PM cents Waveform Delay seconds Sync Phase cycles

Envelope in dB / seconds

Preview gate seconds

ADSR times are seconds, sustain is linear amplitude; straight segments in dB imply exponential amplitude. −96 dB is the engine floor; start/release end become exact zero. Preview is a fresh note, not an oscilloscope: live ADSR edits re-anchor from current dB; key-rate scaling, pitch envelopes, velocity and LFO may alter the actual note.

Canonical patch JSON

Single patch, maximum 16 KiB. Strict validation rejects unknown fields, invalid numbers and non-data objects; legacy input is normalized to version 7. Each operator supports periodic shapes or deterministic held noise. Noise rate is ignored for other waveforms; ratio/fixed-Hz/pitch controls do not pitch noise. Waveform/rate changes retrigger held notes. Square, saw and noise can alias despite oversampling. Export can be passed directly to opm.playNote({ voice: patch, note: 60 }).